Number wheel for counter or the like

ABSTRACT

A number wheel for use in a counter or other like device and embodying a novel construction of a number wheel and operatively associated parts, including a unitary sandwich of the wheel integral with a primary wheel hub, a spring detent member, and a secondary hub, the latter rotatably mounting and confining a driver gear element, with a spring and pawl reset mechanism confined in a recess in the sandwich. Also involved is the method of fabricating such a number wheel by a series of mechanical steps including ultrasonic welding for uniting the wheel hubs in forming the sandwich.

UnitedStates Patent 1 inventor John LAflel [54] NUMBER WHEEL FOR COUNTEROR THE LIKE 11 Chile, 11 Drawing [52] U.S.Cl 235/1 C, 235/117 R [51]Int. C1. 6064! 23/00 v [50] 7 Field ofSenrchW. 235/13,v

[56] I References Cited UNITED STATES PATENTS 1,643,551 9/1927 Friden235/1 2,279,337 4/1942 Niem ann..... 235/] 2,334,465 11/1943 Wood235/133 3,419,297 12/1968 Diepenhorst et a1... 287/189L36 3,448,4646/1969 Jonas 2/336 3,509,614 5/1970 Eldred 29/159 PrimaryExaminer-Stephen J. Tomsky Attorneys-C. Cornell Remsen, .lr., Rayson P.Morris, Percy P. Lantzy, Paul W. Hemminger and A. Donald Stolzy'ABSTRACT: A number wheel for use in a counter or other like device andembodying a novel construction of a number wheel and operativelyassociated parts, including a unitary sandwich of the wheel integralwitha primary wheel hub, a

spring detent member, and a secondary hub, the latter rotatably mountingand confining a driver gear element, with a spring and pawl resetmechanism confinedin a recess in the sandwich. Also involved is themethod of fabricating such a number wheel by a series of mechanicalstepsincluding ul-. trasonic welding for uniting the wheel hubs in formingthe sandwich.

NUMBER wuss]. ron'coumiaims this? This'application is a division ofcopending application, Ser.

No. 669,760 filed on Sept. 22, 1967, for Number Wheel for Counter or theLike and Method of Fabricating the Same. The said patent application hasnow issued into US. Pat. No. 3,507,724. The benefit of the filing dateof said parent application is hereby claimed for this application.

BACKGROUND OF THE INVENTION In counters and other devices of generallysimilar characteristics, it is customary to rotate a number wheel or thelike by means of a cable, shaft, pawl escapement or other means. Thus, amechanism turns the first wheel whereby distance or other measure isrecorded in angular movement of the wheel. When more than one numberwheels are employed, they are usually interrelated by Geneva elementswhereby at the end of a revolution of the first number wheel, a secondnumber wheel is rotated one step, and so on. In certain types ofcounters which can be reset to zero, the transmission between drivergear and wheel must be such that a slip-clutch action permits overridingrotation of the wheel without disconnecting the drive connection to thedriver gear.

Number wheels are disclosed in the prior art but so far as applicant isaware they have been mechanical assemblies tedious and expensive to puttogether, somewhat excessive in weight, and lacking permanent simplifiedunification SUMMARY OF THE INVENTION The number wheel of the presentinvention is compact, lightweight, conveniently fabricated, and embodiesa unique permanent sandwich-type assembly of wheel, driver gear andratchet-type slip clutch.

The objective is accomplished by forming a wheel in generally cup shapeof a material, preferably a plastic which is susceptible to welding byultrasonic vibration. The wheel includes a hub from an end face of whichone or more facets project, the hub including the facets being of thesame material and integral with the wheel. A spring detent member ispositioned against a web of the hub, being located by apertures throughwhich the facets extend.

A secondary hub member made of the same material as the wheel, or anysuitable material which can be ultrasonically welded thereto is utilizedto rotatably mount the diver gear.

The driver gear is made of lightweight material, preferably a plastic,but of a character which will not weld to the hubs. It is retained onthe secondary hub by a thrust flange integral with the hub.

The secondary hub, carrying the driver gear, is permanently attached tothe primary hub. It is conveniently centered thereon by fitting over astub extension of the primary hub. The preferred method of attachment isto subject the assembled parts to pressure and vibration by anultrasonic generator, which will weld the two hubs into a unitaryhomogeneous and integral component.

The ratchet-type slip clutch comprises a surface on the driver gearformed with radially extending ratchet teeth, cooperatively engagingwith the spring detent. The resilient engagement is adequate for thedriver gear to turn the lightweight wheel, but will yield when thedriver gear is restrained and the wheel is forcibly rotated forresetting the latter.

A spring-biased pawl is nested in a recess in the composite hubassembly, being heldbetween adjacent surfaces of the primary hub and thespring detent member. The pawl rides freely in and out of a notch in areset shaft when the driver gear is allowed to advance the wheel, butdrops into the notch and is retained there when the shaft is rotated inthe resetting direction.

The river gear may be rotated by any mechanical means such as gearing,ratcheting, etc. The wheel may have appended thereto a Geneva tooth fortransfer of rotation in predetermined increments from one number wheelto an adjacent one.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation of anumber wheel made in accordance with the invention.

FIG. 2 is a similar view, enlarged and partly in section.

FIG. 3 is a vertical sectional view taken on the line 3-3 of FIG. 2.

FIG. 4 is a vertical sectional view taken on the line 4-4 of FIG. 2.

FIG. 5 is a fragmentary side view of a Geneva tooth transfer on thewheel.

FIG. 6 is a perspective of the pawl reset member.

. FIG. 7 is a perspective of the spring which biases the pawl.

FIG. 8 is an exploded view partly in section of the parts which make upthe number wheel, with a pressure plate and an ultrasonic generatorindicated schematically.

FIG. 9 is a vertical sectional view of the parts of FIG. 8 aspermanently assembled. I

FIG. 10 is an enlarged fragmentary view sembled before welding.

FIG. 1 l is a similar view after welding is completed.

showing parts as- DESCRIPTION OF THE PREFERRED EMBODIMENTS The wheel isgenerally cup shaped. The wall of the cup is in the form of a planecylindrical wheel rim 21 on which any desired numbers 22 may appear, asfor example 0 through 9, or more. The rim is made relatively thincompared to the wheel hub 23, which latter is mountable on a reset shaft24. The inner end of the hub is enlarged into an annular web 25, and afrustoconical wheel disk 26 extends from the web into conjunction withthe rim.

The wheel initially is provided on the end surface of the annular web 25with a plurality of facets 30 which are used as locaters for a springdetent member 31 and as welding at tachments for a secondary hub 32.

The annular web 25 is also formed with an elongated recess 33 which hasopen communication with the interior of the wheel hub. This recess isspecially formed with enlarged circular ends 33' and 33". A pawl 34 anda generally hairpinshaped spring 35 are oppositely mounted in therecess, with the spring biasing the shank of the pawl against the shaft.Pawl and spring are each shaped with an enlarged end which fits into theends 33' and 33" respectively of the recess for maintaining the pawl andspring captive in the recess. The shaft has a notch 36 in verticalalignment with the pawl. When the wheel is rotated in a direction toadvance the numbers (FIG. 3), the pawl rides over the shaft. When theshaft is rotated to reset the wheel, the pawl becomes engaged in thenotch to transmit the rotation to reset the wheel (FIG. 4). The pawl andspring may be reversed in position, whereby the wheel is renderedbidirectional.

A generally annular stub extension 37 extends inwardly from the web 25as a continuation of the hub 23. It is interrupted at 38 where therecess 33 communicates with the interior of the hub. At its outer end abore 39 is formed to accommodate a ring 40 which axially positions thewheel on the shaft. Thus, in the event of high temperature or humidity,a set of wheels will not have a thermoexpansion which will cause them tocontact one another. Misalignment of spur gears is also therebyprevented.

The detent member 31 is in the form of a thin disk 41 with springcharacteristics. It has a central aperture 42 which fits over theextension 37, and it also has a plurality of smaller apertures 43 whichcan register with the welding facets 30. These facets extend through theapertures 43, and the latter preferably are of a diameter greater thanthat of the facets for reception of flowable material when welding takesplace.

On the inner face of the disk 41 one or more detents (teeth) 48 may beprovided. Conveniently, they may be struck from the material of the diskitself, and preferably there are two of them diametrically spaced togive proper balance. I

Contiguous to the disk is positioned the secondary hub 32. It has asocket 49 which is engageable with the extension 37 to axially relatethe parts. It is welded to the annular web 25 through the agency of thefacets 30 in a manner to be later described. The secondary hub embodiesa rim 50 terminating in a flange 51. The rim 50 provides an axle-typebearing for a driver gear 52, and the flange 51 functions as a thrustretainer of the gear, confining the latter between the disk 41 and theflange 51, the gear 52 being rotatable on the rim 50.

The gear 52 includes a relatively large-diameter'section 53 withperipheral teeth 54 which can be engaged by any suitable driver, as forexample by a spur gear 55 taking rotation from a source to be measured.

The driver gear also includes an annular axial offset 56 of relativelysmaller outside diameter (corresponding generally to the outsidediameter of the detent disk 41). The face of the annular offset isformed with radially extending ratchet teeth tent disk'through theratchet teeth 58 resiliently engaged by V the detents 48. By the rigidsecurement of the detent disk to the annular web 25 the wheel is rotatedin a counting direction. 7

The wheel may be provided with Geneva teeth 60 engageable by anysuitable Geneva element 61 for transferring rotation of the wheel toanother wheel in series.

For resetting the wheel, the shaft 24 is manually rotated so as to bringthe notch 36 into engagement with the pawl 34, and the latter transmitsrotation to the hub assembly. The gear section 53 is restrained by thespur gear during reset. However, the resiliency of the detent member 31permits the detents to ride over the ratchet teeth 58, and the wheel maybe turned to zero or to any number desired.

The method of fabricating the wheel is an important phase of theinvention. It avoids the use of screws, clamps, adhesives, and any otherconventional assembly devices, which are cumbersome and difficult toemploy, especially in miniature-size number wheels. Furthermore, itresults in a unified assembly which will remain intact under allordinary service conditions.

The wheel and the secondary hub are formed of ultrasonically weldableplastic, one example of which is nylon.

The detent spring disk and its teeth may be satisfactorily formed of anyspring material.

The driver gear should not be ultrasonically weldable under the sameconditions that the wheel and hub are weldable. A good material for thatpurpose is a tough plastic available as Du Pont Delrin Acetal.

These named materials are by way of illustration and not of limitation.

In completing the assembly a fixture should be held on one side, asillustrated in FIG. 8 and an ultrasonic vibration should be applied tothe other side. A suitable ultrasonic generator, which is known,produces vibrations at a frequency suitable to generate heat between thetwo surfaces so as to weld them. The vibrations are transmitted to theweldable parts through a hornor rod-shaped structure, as schematicallyshown in FIG. 8.

The latter figure in the drawings illustrates the method referred to. Itcomprises the several steps of forming the wheel of an ultrasonicallyweldable plastic with a primary hub having an end surface 62 andincluding a facet of the same material integral with the hub andextending outwardly of the surface parallel to the hub axis, forming asecondary hub of the same material or material adaptable to the sametype of welding, and with an annular bearing surface for a driver gear,and with an end surface 63 suitable for mating with the end surface ofthe primary hub. A spring detent member is formed with an aperturetherein which will allow the facet toextend through. The detent memberis placed against the end surface of the primary hub with the facetextending through the aperture. A driver gear is prepared of a materialnot receptive to ultrasonic welding and this is placed on the bearingsurface of the secondary hub. A pawl and spring are disposed in a recessin the primary hub. The assembly of the gear and secondary hub is thenplaced in axial alignment with the primary hub with its end surfacefacing the end surface of the primary hub.

The assembly is placed in a holding fixture. This is preferablyperformed by disposing the block horizontal (90 from the position shownin FIG. 8) and stacking the parts thereon. A vibratory condition is thenimparted to the hubs by an ultrasonic generator to weld the facet to theend surface of the primary hub, and thus forming a joint between thehubs resulting in a unitary hub assembly with the detent between the hubin a permanent structure. It is preferably also in forming the secondaryhub to provide a flange to retain the driver gear on the secondary hub.

The vibration imparted by the ultrasonic generator affects only thecontiguous material of the primary and secondary hubs. It appears thatthe facets of the primary hub, become heated and flowable and not onlyfill the space in the aperture of the detent disk but flatten out andweldably merge with the contacting surface of the secondary hub, as seenin FIG. 11, so that when the welding is completed not only is the detentdisk securely. held in place but the primary and secondary hubs arecompletely unitary and for all practical purposes are homogeneous andintegral. Furthermore, the pawl and spring are movably trapped in theirrecess, and the driver gear is captive for rotation on the rim of thesecondary hub.

The wheel (primary) hub, the detent member, and the secondary hub arefixed rigidly, together by the welding, so 7 that there is no axial orradial play between these parts.

The counter wheel of the present invention may be either the unitswheel, the tens wheel, or any other wheel. Further, the units 'wheel maybe driven in step fashion or it may be driven continuously.

Although I have herein shown and described my invention in what I haveconceived to be the most practical and preferred embodiment, it isrecognized that departures may be made therefrom within the scope of myinvention, which is not to be limited to the details disclosed hereinbut is to be accorded the full scope of the claims so as to embrace anyand all equivalent devices and methods. e

What is claimed is:

l. A number wheel for use as a component in a counter or other meter,and comprising: a wheel member with a numeral bearing peripheral rim, aprimary hub, and rigid means interconnecting said rim and hub, asupplemental hub in axial alignment with the primary hub, saidsupplemental hub embodying an annular external bearing surface, a springdetent member interposed between the primary hub and supplemental hub,the two hubs being rigidly interconnected to comprise a unitary hubassembly with the detent member rigidly secured therein, and a drivergear rotatably mounted on said bearing surface, said driver gear beingprovided with an annular ratchet surface lying in a general plane normalto the axis of the hubs and in engagement with the detent member, saidengagement affording sufficient frictional transmission force totransmit rotation of said driver gear to said wheel member to turn thelatter when the hub assembly is free to rotate, but allowing slippagewhen sufficient force is applied to the hub assembly to rotate the samefor resetting the wheel member.

2. A number wheel as defined in claim 1 in which a springbiased pawl ismounted in the hub assembly with its tooth end protruding toward theaxis of the hub and being adapted to ride over the surface of a resetshaft when the wheel member is being rotated in number advancingdirection but engageable in a notch in the shaft when the shaft isrotated for resetting the wheel.

3. A number wheel as defined in claim 1 in which the spring detentmember is formed with an aperture, and means extending through theaperture for interconnecting the primary and supplemental hubs.

4. A number wheel as defined in claim 3 in which said interconnectingmeans comprises a facet integral with and extending from one of the hubsand is welded to the other of the and are welded together by such means.

6, A number wheel as defined in claim 2 in which a recess is formed inthe primary hub, the pawl and its biasing spring are located in therecess. and are confined therein by the union of the primary andsecondary hubs.

' 7. A number wheel as defined in claim 1 inwhich the detent member is adisk having spring characteristics, and detents are formed .On the diskand protrude into engagement with the ratchet surface of the drivergear. e

8. A number wheel as defined in claim] in which the supplemental hub isformed with a thrust flange at its outer end for retention of the drivergear on the supplemental hub.

9. A number wheel as defined in claim 1 in which the wheel member isgenerally cup shaped, the means interconnecting the rim and hub is afrustoconical web affording a housing space inside the lip of the cup.the driver gear is formed with a peripherally toothedsectiondisposedoutside the'lip of the

1. A number wheel for use as a component in a counter or other meter,and comprising: a wheel member with a numeral bearing peripheral rim, aprimary hub, and rigid means interconnecting said rim and hub, asupplemental hub in axial alignment with the primary hub, saidsupplemental hub embodying an annular external bearing surface, a springdetent member interposed between the primary hub and suPplemental hub,the two hubs being rigidly interconnected to comprise a unitary hubassembly with the detent member rigidly secured therein, and a drivergear rotatably mounted on said bearing surface, said driver gear beingprovided with an annular ratchet surface lying in a general plane normalto the axis of the hubs and in engagement with the detent member, saidengagement affording sufficient frictional transmission force totransmit rotation of said driver gear to said wheel member to turn thelatter when the hub assembly is free to rotate, but allowing slippagewhen sufficient force is applied to the hub assembly to rotate the samefor resetting the wheel member.
 2. A number wheel as defined in claim 1in which a spring-biased pawl is mounted in the hub assembly with itstooth end protruding toward the axis of the hub and being adapted toride over the surface of a reset shaft when the wheel member is beingrotated in number advancing direction but engageable in a notch in theshaft when the shaft is rotated for resetting the wheel.
 3. A numberwheel as defined in claim 1 in which the spring detent member is formedwith an aperture, and means extending through the aperture forinterconnecting the primary and supplemental hubs.
 4. A number wheel asdefined in claim 3 in which said interconnecting means comprises a facetintegral with and extending from one of the hubs and is welded to theother of the hubs.
 5. A number wheel as defined in claim 4 in which theprimary hub and the supplemental hub and the facets are formed ofplastic material which can be joined by ultrasonic vibration and arewelded together by such means. 6, A number wheel as defined in claim 2in which a recess is formed in the primary hub, the pawl and its biasingspring are located in the recess, and are confined therein by the unionof the primary and secondary hubs.
 7. A number wheel as defined in claim1 in which the detent member is a disk having spring characteristics,and detents are formed on the disk and protrude into engagement with theratchet surface of the driver gear.
 8. A number wheel as defined inclaim 1 in which the supplemental hub is formed with a thrust flange atits outer end for retention of the driver gear on the supplemental hub.9. A number wheel as defined in claim 1 in which the wheel member isgenerally cup shaped, the means interconnecting the rim and hub is afrustoconical web affording a housing space inside the lip of the cup,the driver gear is formed with a peripherally toothed section disposedoutside the lip of the cup and with an offset extending into the housingspace, the annular ratchet surface being formed on said offset.
 10. Anumber wheel as defined in claim 4 in which the facet is formed on theprimary hub.
 11. A number wheel as defined in claim 1 wherein theprimary and supplemental hubs are formed with mutually facing generallyflat annular ends, the detent member is formed with an aperture inalignment with said ends, and a welded junction is formed between thetwo ends through said aperture.